mercurial/diffhelper.py
author Anton Shestakov <av6@dwimlabs.net>
Mon, 31 Jan 2022 18:13:00 +0300
changeset 48789 ef50a62eec40
parent 46819 d4ba4d51f85f
child 48875 6000f5b25c9b
permissions -rw-r--r--
obsolete: don't use os.stat in repo.obsstore.__nonzero__ if it's static HTTP If a repo is accessed via static HTTP, then we obviously can't use os.stat() to just peek at the file size. Let's download the entire file to check its size. Yes, this feels wasteful, but: 1. If we're cloning or pulling a repo from a static HTTP server, we need the contents of the obsstore anyway. 2. Implementing statichttpvfs.stat() that uses HEAD will result in one more request to a static-only HTTP server, which is already slow. Also parsing a response to a HEAD request to construct os.stat_result is pretty hacky. There's also a question of the remote server properly supporting HEAD method and reporting at least file size. 3. Implementing statichttpvfs.stat() that uses GET is pretty much the same thing as we do here, except we can't even cache the response easily, unlike simply accessing obsstore._data, which is @propertycache'd. Importing statichttprepo locally to avoid circular import. See also: 4507bc001365 and commit message of f8f2ecdde4b5. Differential Revision: https://phab.mercurial-scm.org/D12195

# diffhelper.py - helper routines for patch
#
# Copyright 2009 Olivia Mackall <olivia@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from .i18n import _

from . import (
    error,
    pycompat,
)

MISSING_NEWLINE_MARKER = b'\\ No newline at end of file\n'


def addlines(fp, hunk, lena, lenb, a, b):
    """Read lines from fp into the hunk

    The hunk is parsed into two arrays, a and b. a gets the old state of
    the text, b gets the new state. The control char from the hunk is saved
    when inserting into a, but not b (for performance while deleting files.)
    """
    while True:
        todoa = lena - len(a)
        todob = lenb - len(b)
        num = max(todoa, todob)
        if num == 0:
            break
        for i in pycompat.xrange(num):
            s = fp.readline()
            if not s:
                raise error.ParseError(_(b'incomplete hunk'))
            if s == MISSING_NEWLINE_MARKER:
                fixnewline(hunk, a, b)
                continue
            if s == b'\n' or s == b'\r\n':
                # Some patches may be missing the control char
                # on empty lines. Supply a leading space.
                s = b' ' + s
            hunk.append(s)
            if s.startswith(b'+'):
                b.append(s[1:])
            elif s.startswith(b'-'):
                a.append(s)
            else:
                b.append(s[1:])
                a.append(s)


def fixnewline(hunk, a, b):
    """Fix up the last lines of a and b when the patch has no newline at EOF"""
    l = hunk[-1]
    # tolerate CRLF in last line
    if l.endswith(b'\r\n'):
        hline = l[:-2]
    else:
        hline = l[:-1]

    if hline.startswith((b' ', b'+')):
        b[-1] = hline[1:]
    if hline.startswith((b' ', b'-')):
        a[-1] = hline
    hunk[-1] = hline


def testhunk(a, b, bstart):
    """Compare the lines in a with the lines in b

    a is assumed to have a control char at the start of each line, this char
    is ignored in the compare.
    """
    alen = len(a)
    blen = len(b)
    if alen > blen - bstart or bstart < 0:
        return False
    for i in pycompat.xrange(alen):
        if a[i][1:] != b[i + bstart]:
            return False
    return True